by Robin Erb, Detroit Free Press

by Robin Erb, Detroit Free Press

DETROIT -- The research participant is 383 pounds - the middleweight of the three teenage half-brothers - with skin the color of freshly poured asphalt that stretches across his massive chest and with forearms like tree trunks rooted into hands the size of small melons.

So how do you persuade a wide-awake western lowland gorilla to hold still ... still ... still ... for the itty-bitty adjustments of a chest ultrasound slathered with sticky, cool goo?

With plump strawberries, crunchy veggies and respect.

Loads and loads of respect.

"Oh, we cleared it up right away. I really did," Ann Duncan, the Detroit Zoo's chief veterinarian, said. "I say, 'This is for your heart health and I really need to get these images. It's definitely in your favor if you could cooperate right now.'"

But frankly: "If they don't want to cooperate, we're not going to argue," said Melissa Thueme, the zoo's enrichment technician for primates.

"Seriously," she added - as if there is some confusion, "you don't argue with a gorilla."

With cardiovascular disease the biggest killer of apes in captivity, these heart scans are part of the national Great Ape Heart Project based at the Atlanta Zoo, an effort by North American zoos to better understand the primate heart - how it ticks, how it ages, how it can best be treated. Heart monitors the size of a thumb drive also have been inserted near the spine to track the heart's rhythm as part of the project.

Detroit's participants are the rock stars of Detroit's four-acre African Forest: Chipua, 17, the oldest and more reserved of the three silverbacks, Kongo-Mbeli, 15, the serious, dominant brother, and Pendeka, 16 - the curious, playful middle brother, known for charging the glass at the zoo, scattering startled visitors.

The gorilla heart appears very similar to a human heart, said Dr. Ilana Kutinsky, director of Arrhythmia Services at Beaumont Hospital-Troy and co-founder of the Gorilla Cardiac Database, a collection of 835 videos from apes around North America.

"If you take a heart of a 350-pound human and a 350-pound gorilla and look at them next to each other, you can't tell the difference," she said.

But how do you do even look? Again, respect.

Every few weeks, zoo staff members wheel the zoo's ultrasound machine into the Great Apes holding area.

"For the most part, these three boys want to please us. They seem to enjoy it," Duncan said.

Each of them knows the drill, ambling over to their respective cage doors as soon as they see the stainless steel trays full of fresh produce and other treats, stretching toward the top, curling thick fingers though the steel, and pressing their torsos against the door so the ultrasound probe can be pushed through the steel grate.

This day, Pende is first. The most curious of the three, he has been the most cooperative in recent exams.

"Stay, stay, stay," Thueme says softly - her left hand handing food through the cage door to Pende even as her right hand slides an ultrasound probe over the center of his chest.

"If you were a human having this exam, you would be lying down," Duncan explains later. "They would have you position yourself. 'Roll a little bit to your left' or 'Now do this. Do that.' They'd have your arm stretched out."

Gorillas don't take directions as nicely. They don't hold their breath on cue, either.

And complicating things even further: The person manipulating the probe - Thueme in this case - can't see the screen with its pulsating images of the heart.

As she tries to persuade the gorillas to stand in one place, she's also moving the probe with their breathing and grunting and relaxing - all the while taking direction from Duncan nearby to move the probe to the right, now to the left, angle upward, and over.

"It's like playing a video game when you don't have the controller," Duncan says later, chuckling.

"Stay, stay, stay..." Thueme continues.

The ultrasound machine lets out a soft trill. A good three seconds of video.

Pende is still munching.

In his cage next door, Kongo is stock-still - all 433 pounds of him. Only his head swivels from the staff he knows to a stranger he doesn't.

All this work is allowing researchers to understand that - though they may look the same - the human and gorilla heart age differently.

Human heart disease, for example, usually takes the form of arteriosclerosis, when fatty substances build up inside arteries and clog the heart function. In gorillas, heart disease is more often the slow thickening of muscle walls, ultimately weakening the heart's ability to push through enough blood.

As it turned out, it appeared that Kongo and Chip already are showing signs of heart disease. Both have been on heart medications for more than a year - the same kind given to humans - in hopes of slowing or stopping the thickening.

To be clear, the work here is not designed to help add to the research on human hearts. The goal is to help the great apes.

Still, who can say what might be gleaned in the future? said Kutinsky.

For example, understanding that apes might try to rip out the small devices if implanted under the chest skin, researchers now implant them near the spine. The readings have been surprisingly clear, spurring a discussion about alternative ways to implant the devices in women who have had breast cancer and cannot tolerate an implanted device in their chest wall, for example, she said.

On this frigid day along, the heating system hums. Pende is crunching his vegetables. The ultrasound machines beeps.

Then suddenly crack!

Kongo throws himself at the cage door toward the stranger, the concussion rattling stainless steel bars, reverberating inside this small brick room and sending his two brothers scrambling to the back of their cage.

Silence. And then Thueme chuckles.

"Didn't see that coming," she said. Duncan is shaking her head.

It will take several minutes to cajole Pende back to the ultrasound machine this day, and Kongo eventually ambled up to the probe, too.

But his outburst - and the fact that Chip remained seated far from the cage door - served as a reminder of the sheer power of an animal that some have estimated to have seven times or more the strength of a human. Though they are done on the other side of this cage door, there is no doubt that these tests are on the gorillas' terms.